The present invention relates to a device, system and method for tissue displacement/separation and, more particularly, to a tissue displacement/separation device which can be used to protect healthy tissue from effects of treatment on adjacent treated tissues and yet minimize the physiological impact of displacement on the healthy tissue.
Removal or treatment of pathological tissue such as cancer or any malignant or benign growth or tumor caused by abnormal and uncontrolled cell division can be effected in any one of several well known approaches.
The most common form of treatment is surgery, followed by radiation (external or internal), chemical and thermal therapies. Examples of radiation therapies include but are not limited to external radiation beam therapy and interstitial brachytherapy, a technique in which radioactive sources are placed into the prostate gland, delivering radiation from within the prostate.
Thermal treatment approaches include but are not limited to cryotherapy and thermal ablation. In thermal ablation, a balloon or catheter filled with hot water is used to ablate target tissues. Cryosurgery, on the otherhand utilizes liquid nitrogen or argon gas expansion to injure tissue and is most often used when a tumor is small and cannot be removed using surgery.
Chemical ablation therapy includes use of a variety of chemical agents that kill cells exposed thereto. Chemical ablation utilizes chemical agents such as ethanol or hyperosmolar saline which are capable of causing necrosis to tissue exposed thereto.
Examples of other therapies that can be used for treatment include radio frequency ablation (RFA), a technique that employs high-energy radio frequency energy to destroy inoperable tumors and High Intensity Focused Ultrasound (HIFU), or Focused Ultrasound (FUS) which can be used to rapidly kill tissue such as tumors and to stop internal bleeding by cauterizing injured organs or blood vessels.
The above described treatments approaches can be practiced individually or in combination as adjuvant therapy. In any case, each of the above therapeutic approaches carries some degree of risk of injury to healthy tissues.
For example, during surgery, use of surgical instruments in small, tight spaces can lead to inadvertent tissue injury. Radiation therapy or localized release of chemical substances results in an intensity gradient between the treated tissue and healthy tissue and radiation or chemical injury to healthy tissues. As a result, the total energy or chemical dose for local treatment that can be applied to a tissue is limited by the dose that is inevitably transmitted to healthy adjacent tissues. Moreover, some tissues and organs are more sensitive to radiation and chemical damage than others and thus treatment of tissue adjacent to such tissues and organs can be severely limited.
Thus, there is a great need for an efficient, easy way to shield healthy tissues from the harmful effects of treatment on adjacent pathological tissues, while applying a relatively high and more efficient dose to the pathological tissue. Presently there are a few approaches suitable for separating healthy tissue from pathological/diseased tissue during treatment:
For example, U.S. Pat. No. 5,641,505 describes a material which can be used for tissue separation. The material comprises a porous flexible sheet or tube of a protein-free bioresorbable polymer having pores, which permits the passage of water and salts through the sheet or tube while restricting the passage of cells and other tissue particles. This device is limited in that use thereof in radiation or chemical therapy will lead to undesirable exposure of healthy tissue to radiation energy and chemical agents.
U.S. Pat. No. 5,733,316 discloses a method of providing thermal therapy to prostate tissue of a patient which includes inserting a mechanical separator or infusing a fluid, to separate human tissue to be treated, from non-target tissue, thereby providing thermal insulation and other beneficial effects, and applying the thermal therapy to the target tissue. The method is applied by locating the fluid infusing device at a location adjacent a portion of the patient's prostate and the patient's rectum to provide passage of a volume of a fluid from the device to target location without a containment structure. This approach is limited in that it cannot be used to displace tissue rather just infuse it with a liquid.
U.S. Pat. Application publication No. 20020147386 discloses a method and a device for stabilizing and retracting tissue during surgery, in particular internal tissue. Patches of material, preferably biodegradable, are adhered to tissue surfaces, by manipulation of the patches, for example directly with forceps, or via sutures attached to the patches, tissues can be retracted or otherwise manipulated with minimal trauma to the tissues. While this approach might be useful in some cases, it does not enable rapid uniform tissue displacement.
U.S. Pat. Application publication No. 20040094162 discloses the use of a filler to space a first tissue from a second tissue. Although this application described expandable devices such as balloons and sponges, it does not describe devices which can apply uniform pressure on the displaced tissue.
Thus, although prior art tissue separation approaches are capable of physically separating healthy tissue from treated tissue, and as a result at least partially shielding healthy tissue from the harmful effects of treatment, prior art approaches suffer from several inherent limitations the most prominent of which being an inability to uniformly displace tissue or retain a stable shape throughout the medical procedure.
There is thus a widely recognized need for, and it would be highly advantageous to have, a tissue displacement/separation device which can be utilized to protect healthy tissue from the harmful effect of treatment conducted on an adjacent pathological tissue while minimizing any harmful effects on healthy tissue that may be generated by displacement thereof.